Sub-assembly mounting system

ABSTRACT

A mounting arrangement for a modular component such as a fuel tank on a vehicle includes sub-assembly of the fuel tank on a carrier for installation on the chassis. Alignment is provided by alignment arms extending outwardly from the chassis cooperating with mounting tabs disposed downwardly from the module. The alignment arms are members of a pair of brackets which are attached to the frame rails. The module rests on the brackets when lowered onto the chassis. Frame and module are connected by fasteners between the brackets and the mounting tabs.

BACKGROUND OF THE INVENTION

1. Technical Field

The present invention relates to a mounting arrangement for asub-assembly on a vehicle and more particularly to a mountingarrangement and method for modular components and sub-assemblies such asfuel tank modules across a vehicle frame.

2. Description of the Problem

Trucks are built on frames which serve as foundations for the vehicle'sbody and as a plafform on or to which various components may be mountedor attached. A typical full perimeter frame includes, among othercomponents, two longitudinally extending frame rails. The rails arecommonly connected to one another by several latitudinal cross members.The cross members provide lateral and torsional rigidity to the frameassembly. One cross member will typically be positioned to support atruck cab. Components, such as fuel and hydraulic tanks, may be mountedacross the frame rails perpendicular to the direction of elongation ofthe vehicle.

Back of cab fuel tank modules are known which are supported across theframe rails as illustrated in FIG. 3. In this design, mounting bracketsdescend from the bottom of the tank module, which allows for attachmentto mounting points on the frame rails. The mounting brackets providegood side-to-side alignment, but do not provide fore/aft positioning orgood vertical positioning to allow the introduction of fasteners.

Assembly of vehicles would be eased if fuel tank modules wereautomatically aligned with the correct position on the vehicle chassisfor attachment to the chassis as the fuel tank modules were positionedon the vehicle.

SUMMARY OF THE INVENTION

The present invention provides a vehicle chassis with a modularsub-assembly such as a tank for fuel or hydraulic fluid. The vehiclechassis has first and second longitudinally aligned frame rails. Eachframe rail has an outwardly oriented side. First and second rail sidebrackets are mounted to the outwardly oriented sides of the first andsecond frame rails, respectively. Each rail side bracket has a pair ofoutward extending, parallel guide or alignment arms. The module issupported latitudinally across the frame rails from an elongated carrierforming the bottom of the module. The elongated carrier is supportedfrom below on back edges of the first and second rail side brackets.Four mounting tabs descend from the elongated carrier, extendingdownwardly from the module. Each mounting tab has a one to onecorrespondence with a different, alignment arm. The four mounting tabsare spaced to straddle the frame rails to the outside and to bracket thealignment arms as the module is lowered onto the chassis. To effect thiscooperation the mounting tabs have alignment edges along one side facingthe outside face of the frame rail and leading cam sections along thebottom portion of the mounting tab. The alignment edges urge the moduleinto the correct side-to-side position working against the frame railsand the cam sections urge the module into the correct fore/aft positionworking against the alignment arms. The module is vertically positionedby the support provided the module from the back edges of the rail sidebrackets. Fastening points are provided through the guide/alignment armsand mounting tabs.

Additional effects, features and advantages will be apparent in thewritten description that follows.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features believed characteristic of the invention are setforth in the appended claims. The invention itself however, as well as apreferred mode of use, further objects and advantages thereof, will bestbe understood by reference to the following detailed description of anillustrative embodiment when read in conjunction with the accompanyingdrawings, wherein:

FIG. 1 is a perspective view of a vehicle chassis.

FIG. 2 is a partial view of a pair of frame rails from the vehiclechassis of FIG. 1.

FIG. 3 is a partially exploded view of a prior art fuel tank module andchassis combination.

FIG. 4 is a partially exploded view of a modular fuel tank sub-assemblyand chassis combination in accordance with one embodiment of the presentinvention.

FIG. 5 is a front elevation of the modular fuel tank sub-assembly aspositioned on the parallel frame rails of the chassis.

FIG. 6 is a side elevation of the modular fuel tank sub-assembly.

FIG. 7 is a perspective view of the modular fuel tank sub-assembly.

FIG. 8 is a perspective view of the modular fuel tank sub-assemblyattached to a vehicle chassis.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the figures and in particular to FIG. 1, a perspectiveview of a vehicle chassis 10 is illustrated. The foundational componentof chassis 10 is a box frame 12. Frame 12 provides connection points forsuspension elements for numerous vehicle components, including by way ofexample, rear axle 18 and front axle 19. Rear wheels 20 and front wheels22, are mounted on axles 18 and 19, respectively. Frame 12 carries anengine 14 and dash panel 16 and provides a base for the construction ofa body (not shown) and a place to position the modular tank of thepresent invention.

FIG. 2 illustrates that box frame 12 is constructed in part from twoelongated frame rails 24 and 26, each of which run substantially thelength of a vehicle and which lie parallel to one another. Frame rails24 and 26 are held parallel to one another by a series of cross members,here arranged perpendicularly to the frame rails, although otherorientations for cross members are possible. Among the cross members isan intermediately positioned, cab support cross member 30. The cabsupport cross member 30 supports a driver and passenger cab positionedon frame 12.

Frame rails 24 and 26 have top and bottom flanges 47 and 45,respectively (visible on frame rail 26). Flanges 47 and 45 of both rails24 and 26 extend inwardly toward the centerline of the frame 12, asillustrated by the flanges from frame rail 26. Flanges 45 and 47 giveframe rails 24 and 26 their characteristic C cross sectional shape withflange 45 providing an upper surface. Numerous holes 39 pass throughframe rails 24 and 26 to provide support points for the insertionmounting components such as bolts. Nut and bolt combinations 50 areillustrated in association with cross member 30, providing connection ofmounting hardware for the cross member to frame rail 24.

Referring to FIG. 3 a prior art method of installing a fuel tank module40 on a pair of frame rails 24, 26 is illustrated. Fuel tank module 40comprises a fuel tank 42 set in an elongated carrier 44 which may beconstructed of support rails 60 and end plates 62 to form a rectangularcradle to receive the bottom portion of the fuel tank. Carrier 44supports fuel tank 42 from underneath and provides a frame which may berested across frame rails 24 and 26. The fuel tank is held in carrier 44by straps 61 which are wrapped across the top of the tank from eachside. Extending downwardly from carrier 44 are two mutually spacedmounting brackets 64 and 66. Mounting brackets 64, 66 are spaced to fitaround the relative outside faces of frame rails 24 and 26. The outsidefaces (including outside face 25 for frame rail 24) are flat facesoriented facing away from the longitudinal centerline of chassis 10.Right side mounting bracket 66 includes a bottom edge 68 which is turnedoutwardly relative to frame rail 26 at the bottom of the bracket toallow some initial side to side play in fit as fuel tank module 40 islowered onto a vehicle chassis. The minimum spacing between brackets 64and 66 is however set to much closer tolerances to provide a snug fitfor the brackets around frame rails 24 and 26. This provides good sideto side positioning of the fuel tank module 40, however, it leaves it tothe production workers on the line to adjust the front to back andvertical position of the fuel tank module to bring attachment points 41on the mounting brackets into alignment with attachment points 39 inframe rails 24 and 26.

Referring now to FIG. 4, a partially exploded view of a vehicle chassisand fuel tank assembly is illustrated with a sub-assembly, here a fueltank module 70, shown above its mounting position across vehicle framerails 24 and 26. In the present invention, as distinguished from theprior art described with reference to FIG. 3, the mounting hardware isdivided between portions installed on frame rails 24 and 26 prior tomounting of the fuel tank module 70, namely side rail brackets 80 and82, and those components descending from the fuel tank module, namelyfour mounting tabs 71, 72, 73 and 74 (with mounting tabs 73, 74 shown inFIG. 7). Side rail brackets 80 and 82 are C-channel shaped metalcomponents, attached along back sections 97 and 99, respectively, to theouter faces of frame rails 24 and 26. Conventional fasteners, such asnuts and bolts, may be used to mount side rail brackets 80, 82 from theouter faces of frame rail 24 and 26, with the bolts positioned throughmounting hole attachment points 39 in the frame rails and openingsthrough the back sections 97, 99 of the side rail brackets. Side railbrackets 80 and 82 each include two outwardly oriented arms or guidearms, including guide arms 86 and 88 from side rail bracket 80 and guidearms 87 and 89 from side rail bracket 82. Attachment of fuel tank module70 to frame rails 24, 26 is effected by attachment of the four mountingtabs 71-74 to the guide arms of the two side rail brackets 80, 82.

Rail side brackets 80, 82 cooperate with mounting tabs 71-74 to providefront to back positioning of fuel tank module 70. Rail side brackets 80,82 further provide a support for elongated carrier 44 to position fueltank module 70 vertically. Rail side brackets 80 and 82 are located onframe rails 24 and 26 to leave the topmost portions of back sections 97and 99 extending above the upper faces of frame rails. This arrangementpositions support edges 81 and 83 to support elongated carrier 44 fromits bottom surface, or the bottom surface of its exterior rails 60.Guide arms 86-89 are truncated right triangular shaped projections, withone base providing juncture with the respective back sections of therail side brackets 80, 82. Attachment points 139 are provided througheach of the guide arms 86-89 and attachment points 239 are providedthrough mounting tabs 71-74. A step 101 is illustrated extending pastone end 62 of elongated carrier 60.

Mounting tabs 71-74 cooperate with frame rails 24, 26 to locate fueltank module 70 from side to side over the frame rails. Referring to FIG.5 mounting tabs 71 and 72 may be seen to descend from side rail 60 ofelongated carrier 44, extending downwardly from the carrier (in itsusual orientation) to the relative outside of chassis 10 as defined byframe rails 24 and 26. Mounting tabs 73 and 74, which do not appear inthis figure operate in the same fashion and the discussion relating totabs 71 and 72 is equally applicable to them. Side rail brackets 80, 82are deleted from FIG. 5 to better illustrate the interaction of mountingtabs 71 and 72 with frame rails 24 and 26. The relative interior edges171 and 172 of mounting tabs 71 and 72, respectively, are angled awayfrom the outer faces 27 and 25 from top to bottom. Interior edges 171and 172 function as cams against the upper edges of outer faces 27 and25 to urge fuel tank assembly 70 toward a centered position over framerails 26 and 24 as the fuel tank assembly is lowered onto the rails,even if the fuel tank assembly is initially somewhat misaligned relativeto the chassis.

Referring to FIGS. 6 and 7, the operation of mounting tabs 71-74cooperating with guide arms 86-89 to effect correct positioning of thefuel tank assembly from front to back along chassis 10 is illustrated.Frame rails 24 and 26 are deleted from the drawings for clarity ofillustration. Each of mounting tabs 71-74 corresponds with one of guidearms 86-89. The correspondences are as follows: mounting tab 71 withguide arm 87; mounting tab 72 with guide arm 86; mounting tab 74 withguide arm 88; and mounting tab 73 with guide arm 89. When fuel tankassembly 70 is fully lowered onto frame rails 24 and 26, front to backpairs of mounting tabs snugly bracket to the outside front to back pairsof guide arms. A front to back pair of guide arms are the guide armsextending from a particular side rail bracket. Front to back pair ofmounting tabs 71, 73 corresponds to the guide arms of side rail bracket82 and front to back pair of mounting tabs 72, 74 corresponds to theguide arms of side rail bracket 80.

The lower edges of mounting tabs 71-74 turn outwardly from thecorresponding guide arms for each mounting tab, thereby providing lowercam sections 171-174. When fuel tank module 70 is lowered onto rail sidebrackets 80 and 82, alignment need not be initially perfect. Any of camsections 171-174 may impinge against its corresponding guide arm,resulting in the fuel tank module 70 being urged forward or backwardinto alignment on the guide arms, assuring alignment of the attachmentpoints on the mounting tabs with attachment points on the guide arms.Alignment of mounting tabs 71-74 with guide arms 86-89 may be assured byfixing the side rail brackets 80 and 82 when attaching them to framerails 24, 26.

Referring to FIG. 8, the completed assembly of fuel tank module 70 onframe rails 24 and 26 is illustrated. Fasteners 139 are installed toattach side rail brackets 80 and 82 to frame rails 24 and 26 and toattach mounting tabs 71 and 72 to side rail brackets 80 and 82.Fasteners 139 are typically nut and bolt combinations, with the boltsbeing oriented through the guide arms and mounting tabs so that nuts areattached to the relative outside of the assembly, i.e. from in front ofand behind fuel tank module 70.

Installation of the fuel tank module 70 on frame rails 24 and 26involves first installing side rail brackets 80, 82 on the frame rails.The sub-assembly of the fuel tank module 70 is then lowered onto theframe rails, oriented with the mounting tabs 71-74 downwardly orientedand approximately over their corresponding guide arms. Assuming fueltank module 70 is not perfectly aligned, as fuel tank module 70 islowered one or more of the mounting tabs encounters either one of theguide arms 86-89 along a cam section or one of the frame rails 24, 26against an alignment edge. Contact urges fuel tank module 70 either tothe left or right and either forward or backward to fix the fuel tankmodule's position. As fuel tank module 70 becomes fully lowered, itscarrier 44 comes to a rest on support edges 97 and 99, supporting thevertical position of the module. The invention allows assembly of thefuel tank module on the vehicle chassis with a minimum of direct laborinput devoted to alignment.

While the invention is shown in only one of its forms, it is not thuslimited but is susceptible to various changes and modifications withoutdeparting from the spirit and scope of the invention.

1-10. (canceled)
 11. A method for mounting a module across a pair offrame rails of a motor vehicle chassis, the method comprising the stepsof: mounting a pair of side rail brackets longitudinally aligned on oneanother on outside faces of the frame rails, each of the side railbrackets having a horizontal back edge extending above a top face of itsrespective frame rail and two alignment arms extending outwardly fromthe frame rail and perpendicular thereto; providing four mounting tabson the module, each mounting tab extending downwardly from the module ina usual orientation of the module, the mounting tabs being disposed atthe four corners of a rectangle with each mounting tab having a lead camsection and an alignment edge; lowering the module onto the pair offrame rails in an orientation bringing each of the four mounting tabsinto proximity to a different one of the alignment arms, with thealignment edges guiding side to side positioning of the module byinteraction against the frame rails and the lead cam sections guidingpositioning of the module fore to aft by contact with the alignmentarms; and resting the module on the horizontal back edge of the siderail bracket to complete alignment of the alignment arms and themounting tabs.
 12. A method for mounting a module as set forth in claim11, further comprising the step of: attaching the mounting tabs and siderail brackets using conventional fastening means.
 13. A method formounting a module as set forth in claim 12, further comprising the stepsof: assembling the module prior to installation on the vehicle chassisfrom a carrier and a fuel tank.